As an antibacterial agent, a compound having the following structure (hereinafter, referred to as doripenem, (+)-(4R,5S,6S)-6-[(1R)-1-hydroxyethyl]-4-methyl-7-oxo-3-[[(3S,5S)-5-sulfamoylaminomethyl)pyrrolidin-3-yl]thio]-1-az abicyclo[3.2.0]hept-2-ene-2-carboxylic acid) is known (Patent Literature 1).

In general, for dissolving a suspension (also referred to as slurry) of a compound, a method of dissolving the suspension by heating it is known.
In a heating step, a continuous heating method, and a batch manner heating method are known. The continuous heating method is a heating method in which only a necessary amount is dissolved by heating to an objective temperature while a majority is placed under the cooling environment, this is successively repeated and, finally, a heated and dissolved one is collected. To the contrary, the batch manner heating method is a heating method in which the suspension continues to undergo heating load until a whole reaches an objective temperature.
For example, in the case of a compound which is unstable to heat, a decomposition amount thereof is influenced by a temperature and a time when exposed to the temperature environment. That is, when a solution in which a compound unstable to heat is dissolved is produced, a whole slurry undergoes heating load, and decomposition of the compound progresses until the compound reaches a goal temperature, and is dissolved, in the case of a batch manner. To the contrary, in the case of a continuous manner, decomposition of a compound is prevented by placing a whole slurry under the cooling environment, the slurry is rapidly elevated in temperature, and dissolved little by little and, after dissolution, the compound is rapidly cooled and crystallized, thereby, decomposition of the compound can be suppressed minimum.
If a whole slurry is dissolved by elevating a temperature in a batch manner, as compared with continuous elevation of a temperature, for example, a required time until the slurry reaches a goal temperature can be around 1/20, depending of a scale.
In addition, as a continuous heating and dissolving equipment which can heat a solution by a continuous heating method, a commercially available machine may be also used.
In addition, Patent Literature 2 describes, as a method of sterilizing a drug composition containing a suspension of a drug, a method comprising a step of rapidly heating the drug composition from an ambient temperature to a high temperature, a step of maintaining a drug composition at the high temperature or at a higher temperature for a certain time, and a step of rapidly cooling the drug composition to an ambient temperature.                [Patent Literature 1]        Japanese Patent No. 2,542,773        [Patent Literature 2]        Japanese Patent Application National Publication (Laid-Open) No. 2004-513749        